Pattern assembly for a foundry core unit for casting a cylinder block of a multi-cylinder internal combustion engine

ABSTRACT

The core-making pattern assembly is comprised of two side pattern members having a plurality of recesses corresponding to the number of cylinders in a V-type internal combustion engine. A movable member is mounted in each recess and carries a core section for shaping an engine cylinder bore.

United States Patent 11 1 Kawai 1 Apr. 17, 1973 [54] PATTERN ASSEMBLYFOR A [56] References Cited FOUNDRY CORE UNIT FOR CASTING A CYLINDERBLOCK OF A MULTI- UN'TED STATES PATENTS CYLINDER INTERNAL COMBUSTION899,250 9/1908 Gibney .l64/230 ENGINE 1,990,179 2 1935 Gade... ..164/2302,783,510 3/1957 Dolza et al. ..164/137 [75] Inventor: Kiyomitsu Kawai,Osaka,.lapan FOREIGN PATENTS OR APPLICATIONS [73] Assignee; KabushikiKaisha Toyoda jidushok. 1,033,973 7/1953 France ..l64/23O ki Seisakusho,Kiraya-shi, Japan Primary Examiner-J. Spencer Owerholser [22] F'led:Sept 1971 Assistant Examiner-John E. Roeihel 211 App] 177,93 1Att0rneyRichard C. Sughrue et a1.

[57] ABSTRACT [30] Foreign Application Pnonty Data 7 The core-makingpattern assembly is comprised of two Sept. 7, 1970 Japan ..45/7832l ipattern members i g a p y recesses corresponding to the number ofcylinders in a V-type [52] 11.8. CI. ..164/230, 164/137, 164/368internal combustion engine A movable member is [51] Int. Cl. ..B22c7/06, 1322c 13/12 mounted in each recess and carries a core section for[58] Field of Search 164/137, 230, 369,

shaping an engine cylinder bore. 1

1 Claim, 4 Drawing Figures PATTERN ASSEMBLY FOR A rouNnnY cons UNIT FORCASTING A evLINuan BLOCK or a MULTI-CYLINDER INTERNAL coMnusTIoN ENGINEThis invention relates to improvements in and relating to a patternassembly for the manufacture of a foundry core unit for casting acylinder block of a multi-cylinder internal combustion engine.

Separate and attachable cylinder core pieces or other core parts arefrequently manufactured and secured to a core main body so as to providea composite core and avoid the difficult problem of drawing the core outinto unusual configurations.

In the case of the composite core adapted for use in the manufacture ofthe cylinder block casting including the crankcase part of an internalcombustion engine having V-arranged working cylinders. A problem willappear in the region where the cylinder core elements are attached tothe core main body.

In most cases, these cylinder core elements are assembled to the coremain body through high precision male and female mating surfaces andthrough the glueing technique.

It is one of the objects of the present invention to provide a patternassembly for the manufacture of a composite core adapted for molding aV-arranged multicylinder block for an internal combustion engine,capable of avoiding the aforementioned conventional drawback.

These and further features, objects and advantages of the invention willbecome more apparent as the description proceeds by reference to theaccompanying drawings.

In the drawings:

FIG. 1 is a cross-sectional view of a preferred embodiment of thepattern assembly according to the present invention.

FIG. 2 is an exploded sectional viewof the pattern assembly shown inFIG. 1, yet being shown on an enlarged scale.

FIG. 3 is a schematic perspective view of a composite core prepared bythe pattern assembly according to the invention and as a representativeembodiment thereof.

FIG. 4 is a perspective view of an engine cylindermaking core used inthe composite core manufactured by the pattern assembly according to theinvention.

In the following, a detailed description of the invention will be setforth.

In FIG. 1, essential parts of the core-making pattern assembly accordingto a preferred embodiment are shown in section. The illustrated positionis the closed position of the pattern assembly, defining a closed cavitywithin the assembly ready for blow-in molding of the core unit.

Numerals l and 1 represent a pair of side pattern members which can bemoved from their working position shown to their sidewardly retractedposition by respective operating pneumatic or hydraulic pistoncylinderunits, not shown, which are conventional.

A number of cup-shaped separate pieces 2 and 2' ar ranged in line andeach containing a core member 3 or 3' are attached to these patternmembers I and l,

respectively, as shown in FIG. 1. Core members 3 and 3' are previouslyand separately shaped from shellforming resin-coated sand. These coremembers 3 and 3' correspond to those parts of the composite core whichare extremely difficult to draw.

Separate pieces 2 and 2' each have an external axial taper so as to bemovable axially relative to respective side pattern pieces 11 and l,respectively, for easy attachement thereto and detachment therefrom.

Lower pattern member 4 and upper pattern member 5 are arranged to bemoved vertically pneumatically or and 3' are positioned within theinside hollow spaces 6 and 6', respectively, as shown at the lowercorners of FIG. 2 by chain-dotted lines 3" and 3" respectively.

As will be described more fully hereinafter, the core members 3 and 3'are formed with end flanges 7 and 7', respectively, which are to beembedded within the shell-forming material of the main body 10 of thecomposite core unit generally shown at 11. Thus, it will be clear thatthese end flanges 7 and 7' are positioned so as to protrude from withinthe inside spaces 6 and 6 of the separate pieces 2 and 2' when assembledin position as above referred to. It is necessary to select thedirection of insertion of the core members 3 and 3' into respectiveseparate pieces 2 and 2' and the direction of relative movement ofseparate pieces 2 and 2' relative to the side pattern members 1 and 1',respectively, into axial coincidence with each other.

Upon assembly of the core member 3 or 3 destined for molding an enginecylinder bore, with the separate piece 2 or 2', respectively, theelemental assembly 2;3 or 2';3' is then brought from outside intoengagement with receiving recess 8 or 8' formed in theside patternmember 1 or 1' and these parts are locked in their relative position bymeans of proper conventional fixing means, such as bolts and nuts,although not shown only for simplicity of the drawing. g

In the case of the specific embodiment, shown, adapted. for casting thecylinder block for a V-arranged eight-cylinder engine, each side patternmember 1 or 1 carries each four separate pieces 2 or 2, as shownschematically in FIG. 3. I

For manufacturing the composite core according to this invention, sidepattern members 1 and l' carrying the core members 3 and 3 respectively,are advanced oppositely towards each other from their off-serviceposition substantially shown in FIG. 2 to their operating position shownin FIG. I.Then, the lower and upper pattern members 4 and 5 aresimilarly advanced oppositely towards each other from their off-serviceto working position. In this way, a mold cavity 9 is formed in the thuscompleted pattern assembly.

In an alternative way, the separate pieces 2 and 2' combined withrespective core members 3 and 3' may be positioned at the receivingrecesses 8 and 8' and then, the upper and lower pattern members can beclosed.

In FIG. I, arrows B are shown for illustrating the direction ofintroduction of shell-molding resin-coated sand in the manufacture ofthe composite core.

40 mesh wt. 65 mesh 40 wt. 100 mesh 40 wt. I50 mesh 10 wt.

total 100 wt.

binder phenolic resin 2.5 wt. of said sand; hardening agenthexamethylenetetramine dispersing agent calcium stearate wt. of saidbinder;

0.] wt. of said sand.

The blow-in pressure amounted to about 3 kg/cm.

Subsequent to the blow-in molding and baking, the upper pattern member 5is moved upwards in FIG. 1 and then separate pieces 2 and 2' arewithdrawn from position. Next, the lower pattern member 4 is lowered andthe side pattern members 1 and l' are opened. In this way, the compositecore 11 for a cylinder block casting can be taken out from thecore-making pattern assembly.

It is thus seen from the foregoing description that by employing theimproved technical idea proposed by the present invention, the followingadvantages may be obtained.

l. Glueing steps can be obviated, so as to increase the coremanufacturing efficiency.

2. High precision machining at the glueing surfaces can be avoided.

3. Transportion damage of the composite cores can be reduced to apossible minimum.

4. Unintentional disengagement of engine cylinder bore-making coreelements can be reduced to a minimum.

5. Floating disengagement of said core elements from the core main bodyduring of the cylinder block casting may be avoided almost absolutely.

6. Casting fins can substantially be avoided.

7. Positioning and fixation of said core elements can be carried out ina highly simplified and highly reliable way.

The embodiments of the invention in which an exclusive property orprivilege is claimed are as follows:

1. A core-making pattern assembly comprising a plurality of opposinglymovable pattern members including side pattern members adapted forpreparing a composite core for casting a V-arranged multi-cylinder typeinternal combustion engine, said assembly being characterized in thateach of said side pattern members detachably carries a separate piecepositioned in a positioning recess formed in each of said patternmembers, said separate piece carrying in turn a core section adapted forshaping an engine cylinder bore.

1. A core-making pattern assembly comprising a plurality of opposinglymovable pattern members including side pattern members adapted forpreparing a composite core for casting a V-arranged multi-cylinder typeinternal combustion engine, said assembly being characterized in thateach of said side pattern members detachably carries a separate piecepositioned in a positioning recess formed in each of said patternmembers, said separate piece carrying in turn a core section adapted forshaping an engine cylinder bore.